US20220388367A1

Movatterモバイル変換

Info

Publication number: US20220388367A1
Application number: US17/338,094
Authority: US
Inventors: Attila Simofi-Ilyes; John Fleck; Tao Hong; Stanley Simpson
Original assignee: Brose Fahrzeugteile SE and Co KG
Current assignee: Brose Fahrzeugteile SE and Co KG
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2022-12-08
Anticipated expiration: 2041-06-03
Also published as: US11951797B2

Abstract

The cooling pack assembly includes, a shroud, a fan, a first heat exchanger, and a second heat exchanger. The shroud has a plurality of sidewalls including a main sidewall. The shroud further defines an aperture. The fan is disposed within the aperture. The fan is configured to rotate about a rotational axis. The rotational axis is normal to a plane defined by the main sidewall. The first heat exchanger is disposed on at least one of the plurality of sidewalls. The first heat exchanger has a first cross-sectional area substantially parallel to the plane. The second heat exchanger is disposed on at least one the plurality of sidewalls. The second heat exchanger has a second cross-sectional area substantially parallel to the plane. The second cross-sectional area is less than the first cross-sectional area, and the first heat exchanger is disposed between the fan and the second heat exchanger.

Description

TECHNICAL FIELD

The present disclosure relates to reducing noise and vibration within a vehicle cooling system.

BACKGROUND

Many vehicles generally include second cooling systems configured to cool one or more vehicle components. The cooling systems may include a plurality of heat exchangers and a fan assembly configured to provide convection cooling of the heat exchangers. In some vehicles, however, space that would generally receive or house the cooling system may be limited due to other components or systems of the vehicle.

SUMMARY

According to one embodiment, is a cooling pack assembly is provided. The cooling pack assembly may include, a shroud, a fan, a first heat exchanger, and a second heat exchanger. The shroud may include a plurality of sidewalls including a main sidewall. The shroud further defines an aperture. The fan may be disposed within the aperture and may be configured to rotate about a rotational axis. The rotational axis is normal to a plane defined by the main sidewall. The first heat exchanger may be disposed on at least one of the plurality of sidewalls and may have a first cross-sectional area, substantially parallel to the plane. The second heat exchanger may be disposed on at least one the plurality of sidewalls and have a second cross-sectional area, substantially parallel to the plane. The first heat exchanger may be disposed between the fan and the second heat exchanger.

According to another embodiment, a cooling pack assembly for use in a battery-electric vehicle may include a cooling fan module having a support structure, a fan, a motor, a first heat exchanger, and a second heat exchanger. The fan module may include one or more fans and motors such as a multi-fan module. The cooling fan module may include a shroud provided with a main wall and a plurality of sidewalls extending therefrom such that the main wall defines an aperture. The fan may be disposed within the aperture and configured to rotate about a rotational axis. The first heat exchanger may have a first cross-sectional area. The second heat exchanger may be disposed between the main wall and the first heat exchanger and have a second cross-sectional area. The second cross-sectional area may be greater than the first cross-sectional area. The first heat exchanger may be spaced apart from a first sidewall of the plurality of sidewalls by a first distance and a second sidewall of the plurality of sidewalls by a second distance. The first distance may be substantially equal to the second distance.

According to yet another embodiment, a cooling pack assembly is provided. The cooling pack assembly may include a fan assembly, a first heat exchanger, and a second heat exchanger. The fan assembly may include a shroud having a main wall and a plurality of sidewalls extending therefrom. The main wall may define an aperture provided with an inner periphery. The fan assembly may include a fan, disposed in the aperture and configured to rotate about a rotational axis, and a plurality of blades and a band connecting distal ends of the plurality of blades to one another. The band may include an axially extending portion, a vertical portion, and a curved portion extending therebetween. The vertical portion may be axially spaced apart from the main sidewall and the curved portion may be curved around the inner periphery of the aperture. The first heat exchanger may be disposed on at least one of the plurality of sidewalls and may have a first cross-sectional area that may be substantially parallel to the plane. The second heat exchanger may be disposed on at least one of the plurality of sidewalls, and may have a second cross-sectional area that may be substantially parallel to the plane. As an example, the second cross-sectional area may be less than the first cross-sectional area, and the first heat exchanger may be disposed between the fan and the second heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1 depicts an exploded perspective view of an exemplary cooling assembly pack.

FIG.2 depicts a partial cross-sectional view of the cooling assembly pack.

FIG.3 depicts a perspective view of the cooling assembly pack.

FIG.4 depicts a perspective view of another cooling assembly pack.

FIG.5 illustrates a sound behavior graph of fan blade passing tones with respect to rotational speed for the cooling pack assembly in illustrated inFIG.3 and the cooling pack assembly illustrated inFIG.4.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

As used in the specification and the appended claims, the singular form “a,” “an,” and “the” comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

The term “substantially” or “about” may be used herein to describe disclosed or claimed embodiments. The term “substantially” or “about” may modify a value or relative characteristic disclosed or claimed in the present disclosure. In such instances, “substantially” or “about” may signify that the value or relative characteristic it modifies is within ±0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% or 10% of the value or relative characteristic.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). The term “and/or” may include any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Generally, cooling systems include a heat exchanger, such as a radiator and a cooling fan module that is configured to move or displace air from the heat exchanger to a downstream impediment. As one example, the heat exchanger may be a radiator or a condenser that transfers heat from a liquid coolant or refrigerant to an airstream. The heat source may be an internal combustion engine or an electric motor or other heat generating source. The side of the cooling fan module disposed closest to the radiator may be referred to as the upstream side and the side disposed further away from the radiator may be referred to as the downstream side. In one or more embodiments, the downstream impediment may be an internal combustion engine, an electric machine or motor, one or more batteries, or another vehicle component.

In vehicles provided with internal combustion engines (ICEs), the heat exchanger is typically supported by a structural frame, such as the chassis of the vehicle, and the cooling fan module may be supported by the chassis or carried by the heat exchanger. On the other hand, battery-electric vehicles (BEVs) may include a structural shroud that is mounted to the vehicle frame and that is configured to carry one or more heat exchangers. The shroud may have features for vehicle structure interface and may also nest the heat exchanges and the fan and motor. As an example, BEVs may include a first heat exchanger, such as a condenser, and a second heat exchanger, such as a radiator. The size and arrangement of the first and second heat exchangers with respect to the shroud, collectively referred to as a cooling pack assembly, has been shown to alter, such as improve, the acoustic performance of the cooling pack assembly. Improvements to acoustic performance of cooling assemblies, particularly those in BEVs that use motors that are quieter than ICEs, are desired.

Referring generally to the figures, a cooling pack assembly is provided. The cooling pack assembly may include a shroud that may include a plurality of sidewalls. The shroud may be configured to support at least one cooling component. For example, the shroud may be configured to support a first heat exchanger, a second heat exchanger, and a fan assembly. In one or more embodiments, the shroud may be configured to layer each of the first heat exchanger, second heat exchanger, and fan assembly substantially parallel to each other.

The shroud may include a plurality of sidewalls. In some embodiments, the shroud may comprise at least one of an upper sidewall, a lower sidewall, and a lateral sidewall. To allow the flow of fluid through the cooling pack assembly, the plurality of sidewalls may be configured to form a cooling aperture upon assembly. The cooling aperture may be similarly sized to one of the cooling components. For example, the cooling aperture may be similar in size to the first heat exchanger. The cooling aperture may further comprise an inner periphery. The inner periphery may be formed as a barrel. The barrel may extend axially from the main sidewall. As such, the barrel may extend parallel to the rotational axis. In some embodiments, the lateral sidewall may extending between one of an upper and lower sidewall. Further, the lateral sidewall may be configured to support at least one of a first and second heat exchanger.

The plurality of sidewalls of the shroud may be integrally connected. Additionally, or alternatively, at least one of the plurality of sidewalls may be removably connected to another of the sidewalls. As such, the shroud may be defined by an upper portion and a lower portion. The cooling aperture may be defined by the upper portion and lower portion. The cooling pack assembly may comprise an assembly interface. The assembly interface may be used to removably attach cooling components. Once in place, the assembly interface may be used to securely support cooling components. In some embodiments, at least one of the sidewalls may be configured to engage members of a vehicle frame. The engagement may help support the shroud and other cooling components. Further, the vehicle may be a battery-electric vehicle.

The cooling pack assembly may include a first heat exchanger. The first heat exchanger may be used to assist the phase change of refrigerant within a vehicle cooling system. The first heat exchanger may be a condenser. The first heat exchanger may include a first interface. The first interface may be used to removably attach the first heat exchanger to the shroud. As such, the first interface may be used by the shroud to support the first heat exchanger via the assembly interface. The first heat exchanger may have a first cross-sectional area. The first cross-sectional area may be similar in sized to fit within the cooling aperture. The first cross-sectional area may be partially defined by a first width and a first height.

The cooling pack assembly may include a fan assembly. The fan assembly may include a shroud. Additionally, or alternatively, the fan assembly may include a fan interface. The fan interface may be used to removably attach the fan assembly to the shroud. As such, the fan assembly may be used by the shroud to support the fan assembly via the assembly interface. In some embodiments, the shroud may encompass the fan interface. The shroud may define a fan aperture. The fan aperture may be sized to house a plurality of fan blades. The fan blades may be configured to rotate within the fan aperture about a rotational axis. The plurality of fan blades may be configured to rotate on a rotor of a fan motor. The rotor may be disposed substantial about the rotational axis. In some embodiments, the rotor may be disposed along a perimeter of the motor housing. The fan assembly may define a pushing surface and a pulling surface. The pushing surface may correspond with the direction of fluid flowing from the fan assembly. The pulling surface may correspond with the direction of fluid flowing to the fan assembly. The pushing surface may be generally opposite the pushing surface. While the plurality of fan blades may be disposed within the fan assembly, the plurality of fan blades may be biased towards the pushing surface. The fan blades may extend between distal ends extending from each of the blades. The fan assembly may further include a band. The band may include a vertical portion and a curved portion. The band may be spaced apart from the main sidewall. In particular, the vertical portion may be spaced apart from the main sidewall. Further, the curved portion may be curved around the inner periphery of the aperture.

The shroud may be configured to offset cooling components. In one embodiment, the shroud may be attached to a fan assembly such that the fan assembly defines a rotational axis. The shroud may be further attached to the first heat exchanger such that the first heat exchanger defines a first cross-sectional area. Even further, the shroud may be attached to the second heat exchanger such that the second heat exchanger defines a second cross-sectional area. The shroud may be configured such that both the first cross-sectional area and the second cross-sectional area are substantially normal to the rotational axis. In such an embodiment, the first cross-sectional and the second cross-sectional area may be substantially parallel. The shroud may be configured such that the first heat exchanger is general adjacent to the fan assembly on a cooling surface, and generally adjacent to the second heat exchanger on a transfer surface. The cooling surface may be generally opposite of the transfer surface.

In such embodiments, the first cross-sectional area may be greater than the second cross-sectional area. Further, the first width may be greater than the second width. Additionally, or alternatively, the first height may be greater than the second height. In one example, the second cross-sectional area may be 80% of the first cross-sectional area.

The rotational axis may extend substantially central through the first cross-sectional area. In some embodiments, the rotational axis may also extend substantially central through the second cross-sectional area. As such, the second heat exchanger may be substantially adjacent central to the first heat exchanger. Noise produced by the rotation of the fan may be reduced when compared to other configurations, such as those comprising a second heat exchanger having generally the same cross-sectional area as the first cross-sectional area.

In other embodiments, the second heat exchanger may be radially offset from rotational axis. The radial offset may allow the rotational axis to extend through a non-central portion of the heat exchanger. The offset may be a vertical offset. The offset may allow for a top first edge of the first heat exchanger to line flush with a top second edge of the second heat exchanger. In such an embodiment, one of the second width and second height may be generally equal to the first width and the first height. The other of the second width and the second height may be substantially less that the corresponding first width and first height. Noise produced by the rotation of the fan may be reduced when compared to other configurations, such as those comprising a second heat exchanger having generally the same cross-sectional area as the first cross-sectional area or the same central location.

In one or more embodiments, the shroud may be used to support a first heating assembly, generally adjacent to a second shroud, and even further a fan assembly generally adjacent to one of the first and second heat exchangers.

FIG.1 illustrates an exploded view of acooling assembly pack100. The coolingassembly pack100 may include anassembly interface124. Theassembly interface124 includes ashroud427 having a plurality ofsidewalls103. The plurality ofsidewalls103 may include anupper sidewall109, alower sidewall112, and a pair oflateral sidewalls115. Theassembly interface124 is configured to removably attachable to plurality of coolingcomponents121, e.g., heat exchangers. Theassembly interface124 may having atop portion127 and abottom portion130. Theupper sidewall109 is located on thetop portion127. Thelower sidewall112 is located on thebottom portion130. Thelateral sidewalls115 are located in both thetop portion127 and thebottom portion130.

The coolingassembly pack100 may include afirst heat exchanger200. Thefirst heat exchanger200 may include afirst interface206. Thefirst interface206 is configured to removably attach to theassembly interface124. Thefirst heat exchanger200 may include a firstcross-sectional area203. The firstcross-sectional area203 is defined by afirst width136 and afirst height139. Thefirst heat exchanger200 also may include acooling surface209 and a transfer surface. The coolingsurface209 is generally opposite of thetransfer surface212. Even further, thefirst heat exchanger200 may include afirst edge215. Theheat exchanger200 may be a condenser (as illustrated) or may be a radiator.

The coolingassembly pack100 may include asecond heat exchanger300. Thesecond heat exchanger300 may include asecond interface306. Thesecond interface306 is configured to removably attach to theassembly interface124. Thesecond heat exchanger300 may include a secondcross-sectional area303. The secondcross-sectional area303 is defined by asecond width142 and asecond height145. Thesecond heat exchanger300 also may include a receiving surface312. Even further, thesecond heat exchanger300 may include asecond edge309. Theheat exchanger300 may be a radiator (as illustrated) or may be a condenser.

The coolingassembly pack100 may include afan assembly400 supported by theshroud427. Thefan assembly400 may include afan403 and amotor411. Themotor411 is attached to theshroud427 and thefan403 is attached to a shaft of themotor411. Thefan403 includes a plurality ofblades406 mounted on afan hub407. Aband409 connects between distal ends of theblades406.

Thefan403 is operably coupled to amotor411 and configured to rotate about acentral axis415. Thefan assembly400 may include adownstream side424 that corresponds with pushing fluid, and anupstream side421.

FIG.2 depicts a cross-section of theshroud427 andfan assembly400. In cross section, theband409 includes afirst portion430 extending in an axial direction and asecond portion432 extending in a radial direction substantially transverse to the axial direction. Thesecond portion432 is sized to cover a portion of themain wall106.

Theshroud427 defines afan aperture133 configured to receive thefan403. Theshroud427 has abarrel436 that forms the periphery of theaperture133. Theshroud427 also includes a plurality ofstator arms418 that extend radially inward to a motor-mount ring419 that supports themotor411. Thefan aperture133 is sized to fit and receive thefan403. Thefan403 is disposed in theaperture133 with thesecond portion432 of theband409 being partially received in thebarrel436 and with thefirst portion432 of theband409 being axially forward of themain wall106 to define anair gap438. The outer diameter of theband409 may be greater than the diameter of theaperture133.

Referring toFIG.3, a coolingassembly pack500 has a pair of

heat exchangers

502 and504 having a firstcross-sectional area506 and secondcross-sectional area508, respectively. The

heat exchangers

502,504 are arranged to have their cross-sectional area's normal to thecentral axis510 and to have the center points of the

cross-sectional areas

506,508 radially centered on theaxis510. As depicted, both thesecond width512 and thefirst width516 are substantially equal, but thesecond height514 is less than andfirst height518. As such, the secondcross-sectional area508 is less than the firstcross-sectional area506.

FIG.4 illustrates another coolingassembly pack600 having a pair of

heat exchangers

602 and610. LikeFIG.3, thefirst heat exchanger602 has a largercross-sectional area606 than thecross-sectional area608 of thesecond heat exchanger610. UnlikeFIG.3 in which the smaller heat exchanger is vertically centered with the larger heat exchanger, inFIG.4, thesmaller heat exchanger610 is pushed to the top so that the

upper edges

612 and614 are substantially flush with each other.

FIG.5 illustrates asound behavior graph700 of passing blade tones with respect to rotational speed for the cooling pack assembly illustrated inFIG.3 and the cooling pack assembly illustrated inFIG.4. Thesound behavior graph700 has an fan motor speed axis703 and blade passing noiseorder amplitude axis706. The motor speed may be measured in revolutions per minute (rpm). The blade passing noise may be measured by the decibel amplitude of the sound pressure level. The graph displays thefirst sound behavior709 of a first version of a cooling pack assembly, e.g.,FIG.4, as well as thesecond sound behavior712 of a second version of a cooling pack assembly, e.g.,FIG.3. As shown, thesecond sound behavior712 is significantly lower than thefirst sound behavior709 for every entry of the motor speed. While both thefirst sound behavior709 and thesecond sound behavior712 may have a similar inflection point pattern, thesecond sound behavior712 shows steeper slopes, indicating greater reduction rates in blade passing noise. For example, the decline in blade passing noise of thesecond sound behavior712 is much greater than the decline for the first sound behavior. As such, the disclosed system reduces noise of the fan.

100401 While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.

The following is a list of reference numbers shown in the Figures. However, it should be understood that the use of these terms is for illustrative purposes only with respect to one embodiment. And, use of reference numbers correlating a certain term that is both illustrated in the Figures and present in the claims is not intended to limit the claims to only cover the illustrated embodiment.

Parts List

100 cooling assembly pack

103 sidewalls

106 main wall

109 upper sidewall

112 sidewall

115 lateral sidewalls

121 cooling components

124 assembly interface

127 top portion

130 bottom portion

133 fan aperture

136 first width

139 first height

142 second width

145 second height

200 first heat exchanger

203 first cross-sectional area

206 first interface

209 cooling surface

212 transfer surface

215 first edge

300 second heat exchanger

303 second cross-sectional area

306 second interface

309 second edge

312 surface

400 fan assembly

403 fan

406 blades

407 fan hub

409 band

411 motor

415 central axis

418 fan interface

motor-mount ring419

421 downstream side

424 upstream side

427 shroud

430 first portion

432 second portion

436 barrel

438 air gap

502 heat exchanger

504 heat exchanger

506 cross-sectional area

508 cross-sectional areas

510 axis

512 second width

514 second height

516 first width

518 first height

600 cooling assembly pack

602 heat exchanger

606 cross-sectional area

608 cross-sectional area

610 heat exchanger

612 upper edges

Claims

What is claimed is:

1. A cooling pack assembly comprising:

a shroud having a plurality of sidewalls including a main sidewall, wherein the shroud defines an aperture;

a fan disposed within the aperture, the fan being configured to rotate about a rotational axis normal to a plane defined by the main sidewall;

a first heat exchanger disposed on at least one the plurality of sidewalls, wherein the first heat exchanger has a first cross-sectional area substantially parallel to the plane; and

a second heat exchanger disposed on at least one of the plurality of sidewalls, wherein the second heat exchanger has a second cross-sectional area substantially parallel to the plane, wherein the second cross-sectional area is less than the first cross-sectional area, and wherein the first heat exchanger is disposed between the fan and the second heat exchanger.

2. The cooling pack assembly ofclaim 1, wherein a first sidewall of the plurality of sidewalls carries the first heat exchanger and the second heat exchanger.

3. The cooling pack ofclaim 1, wherein the first sidewall is a lateral sidewall extending between upper and lower sidewalls.

4. The cooling pack assembly ofclaim 1, wherein the second cross-sectional area is at least20 percent less than the first cross-sectional area.

5. The cooling pack assembly ofclaim 1, wherein the fan includes, a plurality of blades and a band extending between distal ends of each of the blades, wherein in cross section, the band includes a first portion extending in an axial direction, a second portion extending in a direction substantially transverse to the axial direction, and a third portion extending between the first and second portions, and with respect to the axial direction, the second portion covers a portion of the main wall.

6. The cooling pack assembly ofclaim 1, wherein the first heat exchanger is a condenser.

7. A cooling pack assembly for use in a battery-electric vehicle, the cooling pack assembly comprising:

a cooling fan module including,

a shroud including a main wall and a plurality of sidewalls extending therefrom, wherein the main wall defines an aperture, and

a fan disposed in the aperture and configured to rotate about a rotational axis;

a first heat exchanger having a first cross-sectional area; and

a second heat exchanger disposed between the main wall and the first heat exchanger and having a second cross-sectional area, greater than the first cross-sectional area, wherein the first heat exchanger is spaced apart from a first sidewall of the plurality of sidewalls by a first distance and a second sidewall of the plurality of sidewalls by a second distance to improve acoustic performance, wherein the first distance is substantially equal to the second distance.

8. The cooling pack assembly ofclaim 7, wherein the first sidewall is disposed above the first heat exchanger and the second sidewall is disposed below the first heat exchanger.

9. The cooling pack assembly ofclaim 7, wherein the second sidewall includes a plurality of engagement members configured to engage a frame of the battery-electric vehicle.

10. The cooling pack assembly ofclaim 7, wherein the fan includes a plurality of blades and a circular band connected to distal ends of the blades, the band having an axially extending portion disposed in the aperture and a radially extending portion spaced from the main wall.

11. A cooling pack assembly comprising:

a fan assembly including a shroud having a main wall and a plurality of sidewalls extending therefrom, the main wall defining an aperture provided with an inner periphery, the fan assembly further including a fan disposed in the aperture and configured to rotate about a rotational axis, the fan having a plurality of blades and a band interconnecting distal ends of the blades, wherein the band has an axially extending portion, a vertical portion, and a curved portion extending therebetween, wherein the vertical portion is axially spaced apart from the main sidewall and the curved portion is curved around the inner periphery of the aperture;

a first heat exchanger disposed on at least one the plurality of sidewalls and having, a first cross-sectional area substantially parallel to the plane; and

a second heat exchanger disposed on at least one the plurality of sidewalls and having a second cross-sectional area that is substantially parallel to the plane and is less than the first cross-sectional area, wherein the first heat exchanger is disposed between the fan and the second heat exchanger.

12. The cooling pack assembly ofclaim 11, wherein the inner periphery of the aperture is formed by a barrel axially extending from main sidewall away from the fan.

13. The cooling pack assembly ofclaim 11, wherein the axially extending portion is spaced apart from the barrel in a vertical direction substantially transverse to the rotational axis.

14. The cooling pack assembly ofclaim 11, wherein the first heat exchanger and the second heat exchanger each nest within the plurality of sidewalls.

15. The cooling pack assembly ofclaim 11, wherein a first sidewall of the plurality of sidewalls carries the first heat exchanger and the second heat exchanger.

16. The cooling pack ofclaim 11 wherein the first sidewall is a lateral sidewall extending between upper and lower sidewalls.

17. The cooling pack assembly ofclaim 11, wherein the second cross-sectional area is at least20 percent less than the first cross-sectional area.

18. The cooling pack assembly ofclaim 11, wherein the fan has a flat portion disposed substantially parallel to the main wall.

19. The cooling pack assembly ofclaim 18, wherein the flat portion of the fan is spaced apart from the main wall.

20. The cooling pack assembly ofclaim 11, wherein the first and second cross-sectional areas are vertically centered on the rotational axis.